March 26, 2009 AT 11:12 am

Tweet-a-Watt kits now available…

Tweet-a-Watt kits are now available! A few months ago, using “off-the-shelf hardware”, we modified a Kill-a-Watt(TM) power meter to “tweet” (publish wirelessly) the daily KWH consumed to the user’s Twitter account (Cumulative Killowatt-hours). We released this project as an “Open source hardware” project – in other words, anyone can make these, modify them and make a commercial product from the ideas and methods.

Here’s how it works, the modified Kill-a-Watt uses a “super-cap” to slowly recharge itself, once there is enough power it turns on the Xbee wireless module which transmits the data to a nearby computer (or internet connected microcontroller, like an Arduino) once the power usage for the day is recorded it uses a predefined Twitter account (it can be your own) to publish your daily KWH consumption for the day, multiple units can be used for an entire household.

Energy change and consumption can happen many ways, we feel there is a social imperative and joy in publishing one’s own daily KWH – by sharing these numbers on a service like Twitter users can compete for the lowest numbers and also see how they’re doing compared to their friends and followers. Our system can work with twitter, google app engine or really… anything that can display data.

We also wanted to make it easy for anyone to build these so we have released a kit based on the inquires and demand – you don’t need to be a venture backed company or a giant company with millions of dollars to make your own low cost home power monitoring system.

Please note Kill-a-Watt(TM) power meters are not included, you can get these just about anywhere for less than $20.

Tweet-a-Watt is a DIY wireless power monitoring system. The project uses an ‘off the shelf’ power monitor called the Kill-a-Watt and adds wireless reporting. Each plug transmits the power usage at that outlet to a central computer receiver. The receiver can then log, graph and report the data. This pack contains nearly everything* necessary to build a single outlet monitor and receiver. To monitor additional outlets, you will need an add-on transmitter pack. One outlet can monitor up to 1500 Watts.

What I think would be absolutely awesome would be to remotely control the power of this, as well. For instance, have some sort of server that store parameters. Then, the tweet-a-watt (or other hacked kill-a-watt) notifies the system that currents watts have hit X level.

I think it would be great to set a schedule for my television and DVD player. Combined, they drawn 18 watts of power when they are turned off. 70 watts if they are on. So, if the watts drop below 30 between the hours of 12P-6P (when no one is home), and 9P-6A (when we are likely to be asleep), then turn off the power to the connected device(s), making the power available again after that time is expired.

Interesting idea Dus10. You can in fact get “standby power” devices which will monitor the power usage of a device (eg TV) and when it detects the standby mode (ie. Power draw has dropped to a set level) it will open a switch automatically. You can then turn the device back on, some have IR remote control. Great for reducing standby power usage, which can get quite large.

I would suggest taking your idea one step further. When your total power usage hits X kWh, start turning off “unnecessary” devices (fans, radios, lights, etc) according to what you deem is required. This way you could force your energy usage down!

You guys (along with the apparent ease of this kit) have totally inspired me to begin again my plan for a DIY Total Home/Small-Office Power Monitoring AND Management System. How awesome will it be to never have to be concerned about whether you left X, Y or Z devices on when you’re away from the home/office. To be able to rest comfortably in the knowledge that you are as power-efficient as you want to be, AND to be able to test the effects/power-consumption of new/replacement devices…again, awesome!

I just encountered mention of the Tweet-a-Watt somewhere I didn’t expect it: The American Society of Mechanical Engineers’ Magazine, Mechanical Engineering. (p. 9, April 2009) This is an exciting idea that is certainly in keeping with the rest of the cool stuff Adafruit has produced and deserving of the first place award.